Comparison of urinary bone resorption markers in women of 40-70 years; day-to-day and long-term variation in individual subjects

Objectives: Bone.resorption can be judged using biochemical markers in urin e and blood. Our aim was to study the patterns of markers in the postmenopa usal period. Methods: The urinary excretion of bone resorption markers was tested using different assays. The study was undertaken to determine the da y-to-day and the long-term variation, over 8 years, of these markers in ind ividual women. Results: Over a period of 2 weeks, the median of the day-to- day variation of the pyridinium crosslink markers varied between 12 and 23% , the median value of the long-term variation over 8 years between 10 and 2 1%, for the telopeptide markers median day-to-day variation was 18 and 20% and the long-term variation was 17 and 19%. The correlations between the di fferent crosslink markers varied between 0.63 and 0.92, depending on the ki nd of the crosslink and on the method of determination The two telopeptide markers showed an excellent correlation with r of 0.95. The excretion of al l bone resorption markers varied with postmenopausal age, some differences were found between the crosslink and the relopeptide excretions with age, i n women more than 20 years postmenopausal the telopeptides decrease whereas the crosslinks show an increase. Conclusions: This study shows that crossl inks and telopeptides give similar information on the rate of bone resorpti on: an increase during the first 5 years and a slight decrease in the next 5 years after menopause, discrepancies were found after 10 or more postmeno pausal years. (C) 1998 Elsevier Science Ireland Ltd. All fights reserved.